The present invention relates to a sheet delivery/guide apparatus in a sheet-fed rotary printing press or the like, which performs switching between piling and non-piling (passing) of sheets onto a sheet pile device.
Conventionally, as shown in Japanese Patent Laid-Open No. 2006-36511, a sheet delivery/guide apparatus has been proposed which comprises a pile device on which sheets conveyed by a sheet convey means pile, and a sheet guide means which can move between a guide position where the sheet guide means moves forward above the pile device to guide a passing sheet downstream in the sheet convey direction and a retreat position where the sheet guide means retreats from the guide position and a sheet released from the sheet convey means falls onto the pile device.
As shown in Japanese Patent Laid-Open No. 2004-217343, a sheet delivery/guide apparatus has been proposed which comprises a pile device on which sheets conveyed by a sheet convey means pile, a fan provided above the pile device and blows air to a sheet so that the sheet released from the sheet convey means reliably falls onto the pile device, and a shielding device which closes the intake port of the fan so as to regulate blowing air toward a sheet passing above the pile device.
Each conventional sheet delivery/guide apparatus described above must control the timing when the sheet is released from the sheet convey means, the timing when the sheet guide means moves, and the timing when the fan blows air. When the sheet convey speed increases, however, the time interval between sheets decreases relatively. In this case, if the timing when the sheet guide means moves or the timing when the fan blows air or stops blowing air is controlled after the sheet piles on the pile device completely or passes the pile device completely, the next sheet control operation will be delayed.
When the switching timing is set on the basis that the sheet convey speed is high, if the convey speed decreases, the guide member undesirably moves to the guide position before the sheet piles on the pile device. Accordingly, a sheet which is to pile on the pile device undesirably rides over the sheet guide means. In particular, assume that the driving means for the sheet guide means or for the fan shielding device is an air cylinder. In this case, the operation speed of the air cylinder is constant regardless of the sheet convey speed. The air cylinder thus cannot cope with a change in sheet convey speed, causing the problems described above.